present invention relates to an apparatus for inserting an item, e.g., an intraocular lens and the like, into an eye. More particularly, this invention relates to such an apparatus constructed so as to release the item in response to a change in temperature.
An intraocular lens is implanted in the eye, e.g., as a replacement for the crystalline lens after cataract surgery. Intraocular lenses include an optic, and preferably at least one fixation member, e.g., a haptic, that extends from the optic and becomes affixed in the eye to secure the lens in position. The optic normally includes a transparent or optically clear optical lens. Implantation of such lenses into the eye involves making an incision in the eye. It is advantageous, e.g., to reduce trauma and speed healing, to have the incision sized as small as possible.
Intraocular lenses are known which are deformable during implantation or insertion into the eye. Thus, the lens can be deformed by placing it into an insertion instrument which is then pushed through a tube located in an incision in the eye. As the insertion instrument exits the tube, the instrument opens and the lens is released into the eye. Such an inserting apparatus is disclosed in Bartell U.S. Pat. No. 4,681,102. Although such a system allows one to insert an intraocular lens through a small incision, it often provides insufficient control as to the actual position of the lens in the eye. In addition, such systems tend to be overly dependent on the technique of the individual surgeon involved. An improved insertion system would be advantageous.
Tillay U.S. Pat. No. 4,666,445 discloses an intraocular lens having a lens body, at least one flexible haptic and a component of shape memory alloy operatively connected to the haptic to change the overall dimensions of the lens for implantation of the lens. After implantation, the shape memory alloy, which is an integral part of the implanted lens, remains in the eye. The long term effects, e.g., regarding toxicity and/or other harmful effects, of the shape memory alloy in the eye remain in question. It would be advantageous to use lens materials which have been proven substantially safe when implanted in the eye.